最长公共子序列

public static int longestCommonSubsequence(String A, String B) {
        	// write your code here
		if (A == null || B == null) return 0;
		int aLen = A.length();
		int bLen = B.length();
		int [][]c = new int[aLen + 1][bLen + 1];
		int [][]b = new int[aLen + 1][bLen + 1];
		ArrayList lists = new ArrayList();
		int preI = 0,preJ = 0;
		for (int i = 1; i <= aLen; i++) {
			for (int j = 1; j <= bLen; j++) {
				if (A.charAt(i - 1) == B.charAt(j - 1)) {
					c[i][j] = c[i - 1][j - 1] + 1;
					b[i][j] = 1;
				}else if (c[i][j - 1] >= c[i - 1][j]){
					c[i][j] = c[i][j - 1];
					b[i][j] = 0;//shuiping
					//c[i][j] = Math.max(c[i][j - 1], c[i - 1][j]);
				} else {
					c[i][j] = c[i - 1][j];
					b[i][j] = -1;//shuiping
				}
			}
		}
		for (int i = 0; i < lists.size(); i++) {
			System.out.println(""+A.charAt(lists.get(i)));
		}
		for (int i = 0; i <= aLen; i++) {
			for (int j = 0; j <= bLen; j++) {
				System.out.print(b[i][j] + "\t");
			}
			System.out.println();
		}
		printStr(b, A, aLen, bLen);
        return c[aLen][bLen];
    }
	
	public static void printStr(int [][]b, String A, int i, int j) {
		if (i == 0 || j == 0)return;
		if (b[i][j] == 1) {
			System.out.print("-" + A.charAt(i - 1));
			printStr(b, A, i - 1, j - 1);
		} else if (b[i][j] == 0) {
			printStr(b, A, i, j - 1);
		} else if (b[i][j] == -1) {
			printStr(b, A, i - 1, j);
		}
	}